I always start all my fabric searches with Quiltshops.com. I have ordered online from a bunch of these shops. Since the search always returns a bunch of shops that have a fabric I am looking for I can quickly compare prices. Here's the link-
http://www.quiltshops.com/
Don't use the "item search" on the page that comes up, that one will give you thumbnails of just fabric. Click on the "item search" on the top of the links on the left of the page, that will give you a list of shops and all the fabric within your search criteria. I find it gives me a greater chance of hitting what I am looking for. Just put in Aspen and see what happens.
Good Luck. :)